1 / 16

ADVANCED MECHANICAL DRAFTING

ADVANCED MECHANICAL DRAFTING. LECTURE #6. MMC & LMC. MMC = M aximum M aterial C ondition Largest shaft diameter Smallest hole diameter. Worst case in most assembly situations. LMC = L east M aterial C ondition Smallest shaft diameter Largest hole diameter.

lukas
Télécharger la présentation

ADVANCED MECHANICAL DRAFTING

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ADVANCED MECHANICAL DRAFTING LECTURE #6

  2. MMC&LMC • MMC = Maximum Material Condition • Largest shaft diameter • Smallest hole diameter Worst case in most assembly situations • LMC = Least Material Condition • Smallest shaft diameter • Largest hole diameter Certain uncommon situations only

  3. 1.494 1.490 1.505 1.500 Ø Ø FITS HOLE SHAFT CLEARANCE FIT CLEARANCE AT MMC = 1.500 – 1.494 = .006 CLEARANCE AT LMC = 1.505 – 1.490 = .015

  4. 2.756 2.752 2.747 2.741 Ø Ø FITS HOLE SHAFT INFERFERENCE FIT INTERFERENCE AT MMC = 2.756 – 2.741 = .015 INTERFERENCE AT LMC = 2.752 – 2.747 = .005

  5. 3.321 3.315 3.328 3.319 Ø Ø FITS HOLE SHAFT TRANSITION FIT INTERFERENCE AT MMC = 3.321 – 3.319 = .002 CLEARANCE AT LMC = 3.328 – 3.315 = .013

  6. GENERAL FIT CONCEPT MMC= MAXIMUM INTERFERENCE or MINIMUM CLEARANCE LMC= MAXIMUM CLEARANCE or MINIMUM INTERFERENCE

  7. FITS IN THE MHB • Five Major Fit Classes • RC – running or sliding clearance fits • LC – locational clearance fits • LT – locational transition fits • LN – locational interference fits • FN – force or shrink interference fits • Each fit class contains several subclasses • All values in fit tables must be multiplied by 1000 before using them in calculations

  8. EXAMPLE Calculate Shaft and Hole diameters and clearances or interferences for a Ø1.50” basic mating shaft and hole in the following fit conditions: RC-7 FN-4 LT-3

  9. HOLE SHAFT CLEARANCE .003O @ MMC .0071 @ LMC 1.50 + .0025 = 1.5025 1.50 + 0 = 1.5000 1.50 - .0030 = 1.4970 1.50 - .0046 = 1.4954

  10. HOLE SHAFT INTERFERENCE .0031 @MMC .0015 @ LMC 1.50 + .001 = 1.501 1.50 + 0 = 1.500 1.50 + .0031 = 1.5031 1.50 + .0025 = 1.5025

  11. HOLE SHAFT CLR or INT .0007 INT @MMC .0009 CLR @ LMC 1.50 + .001 = 1.501 1.50 + 0 = 1.500 1.50 + .0007 = 1.5007 1.50 + .0001 = 1.5001

  12. GSH END DESIGN

  13. CHANGING DIMENSION PROPERTIES • Left click on dimension to show grips • Right click to display change menu • Select PROPERTIES • Change or add prefix, suffix, precision, tolerances etc.

  14. ADD PREFIX OR SUFFIX • Prefixes: • 2X, Ø (%%C), R, SØ, SR • Suffixes: • TYP, MAX, MIN, etc.

  15. .877 .872 Ø TYP CHANGE TO LIMIT EXAMPLE: Dimension .875 Lower limit .003 Upper limit .002 Precision 0.000

  16. 1.505 1.497 MOVE DIMENSION OUTSIDE OF EXTENSION LINES

More Related